Testing method for float liquid level transmitter

ABSTRACT

A testing method for float liquid level transmitter first prepares a testing device displaying a basic data screen and receiving basic data corresponding to fields on the basic data screen. The testing device computes the basic data to obtain corresponding standard values and displays the standard values. The testing device fetches displayed valued measured by a float liquid level transmitter and obtains error values by comparing the displayed values with the standard values. The testing device analyzes the error values to provide analyzed data and determines whether the float liquid level transmitter is qualified by reference to an error range. The testing device generates a calibration curve based on the analyzed data and displays the calibration curve.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a float liquid level calibrator, especially to a testing method for calibration record of float liquid level transmitter.

Description of Related Art

The conventional float liquid level transmitter can measure liquid level in a tube or an interface of two liquids with different specific gravities, and send measurement signals corresponding to 4˜20 mA to test whether the liquid level in the tube is qualified.

In testing the float liquid level transmitter, liquid of a specific gravity is poured into the tube and the level of the liquid is changed during pouring the liquid. The float liquid level transmitter displays the data corresponding to different levels of the liquid and the tester manually judges whether the data sent by the float liquid level transmitter is qualified.

However, there are certain problems in manual judgement. When the measured data sent by the float liquid level transmitter has slight deviation with the standard data for the tube, the tester may erroneously judge that the float liquid level transmitter is qualified. This kind of test is not reliable.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a testing method for calibration record of float liquid level transmitter. The basic data is first input to a testing device and the testing device computes the basic data to obtain standard values. The testing device also reads the measured values of the float liquid level transmitter. The testing device determines error values between the standard values and the measured value and determines the float liquid level transmitter is qualified if the error values are within tolerable range.

Accordingly, the present invention provides a testing method for float liquid level transmitter, comprising: a) preparing a testing device; b) displaying a basic data screen and receiving basic data corresponding to fields on the basic data screen; c) the testing device computing the basic data to obtain corresponding standard values and displaying the standard values; d) the testing device fetching displayed valued measured by a float liquid level transmitter of an instrument and obtaining error values by comparing the displayed values with the standard values, the testing device analyzing the error values to provide analyzed data and determine whether the float liquid level transmitter is qualified by reference to an error range; e) the testing device generating a calibration curve based on the analyzed data and displaying the calibration curve.

BRIEF DESCRIPTION OF DRAWING

The features of the invention believed to be novel are set forth with particularity in the appended claims. The invention itself, however, may be best understood by reference to the following detailed description of the invention, which describes an exemplary embodiment of the invention, taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows the flowchart of the method for testing float liquid level transmitter.

FIG. 2 shows the schematic view of the testing device electrically connected to the instrument.

FIG. 3 shows the basic data screen.

FIG. 4 shows the calibration curve.

FIG. 5 shows the calibration report.

DETAILED DESCRIPTION OF EMBODIMENT

FIG. 1 shows the flowchart of the method for testing float liquid level transmitter. The displayed data (measured data) of the float liquid level transmitter can be determined to be qualified or not and printed report for analyzed data and calibration curve can also be obtained.

In step 100, a testing device is prepared to analyze the error between the established data (standard value) and the measured data (measured values) sent by the float liquid level transmitter.

In step 102, data is established and the testing device (not shown) will display a basic data screen with following data fields: a project name field, a determination result field, an instrument number field, an instrument type field, an instrument brand field, a tolerance percentage (%) field, an input (measurement percentage) field, an output (output current range mA) field, a first liquid specific gravity (S1) field, a second liquid specific gravity (S2) field, an instrument length (such as float tube length) field, a set zero percentage (0%) field, a set 100 percentage (100%) field, and an environment information field. The operation interface of the testing device is used to input basic data. In this step, the instrument is float liquid level calibration recorder and the operation interface is composed of a plurality of keys.

In step 104, the basic data is computed. More particularly, the computation unit in the testing device calculates the standard values based on the input basic data (length×specific gravity). In this step the computation unit is, for example, a microprocessor.

In step 106, the computed standard values are stored. More particularly, the computation unit in the testing device stores the computed standard values in the storage unit, where the storage unit is, for example, a memory.

In step 108, the measured values are analyzed. After the standard values are computed from the input basic data, the testing device fetches the measured data (values) from the external float liquid level transmitter and further analyzes (determines) the error values between the measured (displayed) values and the standard values. The testing device determines whether the measured data from the external float liquid level transmitter is qualified or not based on the error values and then shows the result on the display thereof. In this step, the recorded analyzed data comprises input percentage (%), standard values (mA), displayed values (mA) and error values (%).

In step 110, the measurement curve is generated, where the analyzed result in step 108 is drawn and shown on the display of the testing device.

In step 112, the report is finished, where the above analyzed data and curve are sent to a printer for printing.

With reference to FIG. 2, the testing device 1 is electrically connected to the float liquid level transmitter 21 of the instrument 2 (the level-sensing tube). The float liquid level transmitter 21 has liquid-level indications 211 of 0%, 25%, 50%, 75% and 100%. The testing device 1 comprises a computation unit 11, an operation interface 12, a storage unit 13, a display 14 and an output interface 15.

The computation unit 11 is electrically connected to the float liquid level transmitter 21 and computes the input basic data into standard values. The measured values according to the poured liquid into the instrument 2 (the level-sensing tube) is sent to the computation unit 11, whereby the computation unit 11 records the analyzed data and draws calibration curve. In the embodiment, the computation unit 11 is a microprocessor.

The operation interface is composed of a plurality of keys and electrically connected to the computation unit 11. The plurality of keys is operated to input the basic data for the instrument and the basic data is sent to the computation unit 11 for further processing.

The storage unit 13 is electrically connected to the computation unit 11 to store the analyzed result from the computation unit 11, namely, the input percentage (%), the standard values (mA), the displayed values (measured value) (mA) and the error values (%). In this example, the storage unit 13 is a memory.

The display 14 is electrically connected to the computation unit 11 to display the screen of basic data (basic data screen), the data calibration table and the calibration curve.

The output interface 15 is electrically connected to the computation unit 11 and also electrically connected to an external printer (not shown). The data and curve used to show qualification or not are generated by the computation unit 11 and sent to the printer for printing into a calibration report. In this example, the output interface 15 is USB or wireless transmission interface.

After the testing device establishes data, the computation unit 11 computes the standard values (mA) for testing. Afterward, the computation unit 11 analyzes the standard values (mA) with the displayed values (measured values) sent from the float liquid level transmitter 21 and determines whether the displayed values (measured values) are qualified or not. The computation unit 11 records the analyzed data and generates the calibration curve. The analyzed data and calibration curve are sent to the printer (not shown) through the output interface for printing out the analyzed data and calibration curve as calibration report for the float liquid level transmitter 21.

With reference to FIGS. 2 to 4, the testing device 1 is electrically connected to the float liquid level transmitter 21 when the float liquid level transmitter 21 is mounted on the tube 2. A liquid with a specific gravity is poured into the tube 2. The display 14 of the testing device 1 shows at least following fields after the testing device 1 starts testing: project name field 31, determination result field 32, instrument number field 33, instrument type field 34, instrument brand field 35, error tolerance field 36, input (measurement percentage) field 37, output (output current range) field 38, first liquid specific gravity field 39, second liquid specific gravity field 310, instrument length field 311, set zero-percentage field 312, set 100-percentage field 313, and environment information field 314. Moreover, the exemplary basic data input by the operation interface 11 may be as follows:

The input to the instrument number field 33 is LT-1491.

The input to the instrument type field 34 is float type.

The input to the instrument brand field 35 is ABB.

The input to the error tolerance field 36 is 0.5%.

The input to the input (measurement percentage) field 37 is 0˜100%.

The input to the output (output current range mA) field 38 is 4˜20 mA.

The input to the first liquid specific gravity (S1) field 39 is 0.85.

The input to the second liquid specific gravity (S2) field 310 is 0.

The input to the instrument length field 311 is 100 cm.

The input to the environment information field 314 is 30° C., 50% RH.

After above basic data are input and computed by the computation unit 11, standard values (mA) as following table (Data calibration table) will be obtained and the standard values (mA) are stored in the storage unit 13. At this time, the float liquid level transmitter 21 of the tube 2 is electrically connected to the computation unit 11 and liquid of a specific gravity is poured into the tube 2. The liquid level in the tube 2 changes as the liquid keeps pouring, and the float liquid level transmitter 21 transmits corresponding output. For example, the standard value is 4 mA for 0% height of liquid, 8 mA for 25% height of liquid, 12 mA for 50% height of liquid, 16 mA for 75% height of liquid and 20 mA for 100% height of liquid. The float liquid level transmitter 21 generates measurement (namely, displayed values) for different height of liquid and sends the displayed values to the computation unit 11. The computation unit 11 compares the displayed values with the standard values to obtain the calibration table with error values (error percentage) and further judges whether the float liquid level transmitter 21 is qualified.

During testing, the analyzed error percentage can be drawn into a calibration curve as shown in FIG. 4.

Data calibration table Input percentage Standard value Displayed value Error (%) (mA) (mA) percentage 0 4.00 3.9984 −0.01 25 8.00 7.9946 0.01 50 12.00 11.9978 0.07 75 16.00 15.992 0.07 100 20.00 19.9906 −0.03 75 16.00 15.9887 0.05 50 12.00 11.9947 −0.09 25 8.00 7.9924 −0.01 0 4.00 3.9971 −0.02

When the testing device 1 shows the basic data screen on the display 14 thereof, the above data calibration table is also shown on the same screen. Therefore, as user inputs the basic data, the items input through the basic data are also present at fields of Input percentage (%) and Standard value (mA).

FIG. 5 is a schematic diagram for the calibration report of the invention. After the float liquid level transmitter 21 of the tube 2 is tested and calibrated, the tester or the client can print out the calibration report 4, where the calibration report 4 comprises at least the project name 41, the determination result 42, basic data 43, calibration data 44, float liquid level transmitter symbol 45, calibration curve 46 and tester 47.

Although the present invention has been described with reference to the foregoing preferred embodiment, it will be understood that the invention is not limited to the details thereof. Various equivalent variations and modifications can still occur to those skilled in this art in view of the teachings of the present invention. Thus, all such variations and equivalent modifications are also embraced within the scope of the invention as defined in the appended claims. 

What is claimed is:
 1. A testing method for float liquid level transmitter, comprising: a) preparing a testing device; b) displaying a basic data screen and receiving basic data corresponding to fields on the basic data screen; c) the testing device computing the basic data to obtaining corresponding standard values and displaying the standard values; d) the testing device fetching displayed valued measured by a float liquid level transmitter of an instrument and obtaining an error range by comparing the displayed values with the standard values, the testing device analyzing the error range to provide analyzed data and determine whether the float liquid level transmitter is qualified by the error range; e) the testing device generating a calibration curve based on the analyzed data and displaying the calibration curve.
 2. The testing method in claim 1, wherein the fields of basic data in step b comprise a project name field, a determination result field, an instrument number field, an instrument type field, an instrument brand field, a tolerance percentage field, an input field, an output field, a first liquid specific gravity field, a second liquid specific gravity field, an instrument length field, a set zero percentage field, a set 100 percentage field, and an environment information field.
 3. The testing method in claim 1, wherein in step d the values measured by the float liquid level transmitter are conducted by pouring liquid of a specific gravity into the instrument.
 4. The testing method in claim 3, wherein the float liquid level transmitter has liquid-level indications 211 of 0%, 25%, 50%, 75% and 100%.
 5. The testing method in claim 4, wherein the standard value is 4 mA for 0% height of liquid, 8 mA for 25% height of liquid, 12 mA for 50% height of liquid, 16 mA for 75% height of liquid and 20 mA for 100% height of liquid.
 6. The testing method in claim 1, wherein the analyzed data is calibration data including input percentage, standard value, displayed value and error.
 7. The testing method in claim 1, wherein the instrument in step d is float liquid level calibration recorder.
 8. The testing method in claim 7, further comprising step f) printing a report containing the analyzed data and the calibration curve.
 9. The testing method in claim 8, wherein the testing device comprises: a computation unit electrically connected to the float liquid level transmitter, the computation unit configured to compute the input basic data into standard values, the computation unit configured to generate analyzed data by analyzing the standard values with the displayed values, the computation unit configured to record the analyzed data and generate calibration curve based on the analyzed data; an operation interface composed of a plurality of keys and electrically connected to the computation unit, the basic data being input through the operation interface and then sent to the computation unit; a storage unit electrically connected to the computation unit and storing the input percentage, standard value, displayed value and error computed by the computation unit; a display electrically connected to the computation unit and displaying the basic data screen, a data calibration table and the calibration curve; and an output interface electrically connected to the computation unit and outputting the analyzed data and the calibration curve, where the analyzed data and the calibration curve are printed in a calibration report.
 10. The testing method in claim 9, wherein the calibration report comprises a project name, a determination result, the basic data, the calibration data, a float liquid level transmitter symbol, the calibration curve and a tester. 